Omega Centauri Observatory
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Omega Centauri Observatory clear sky chart from 2005-11-05 to 2017-04-25.

This page is a summary of past forecasts. Even though it's based only on forecasts, some people use these pages as clue to a site's climate. But climate data based on actual observation should be preferred (if you can find it!).

Cloud, Transparency and Seeing forecasts are summarized individually. But because good observing conditions require a combination of minimum cloud cover, transparency and seeing, the individual forecast summaries can be difficult to interpret. The observing conditions section counts the combinations of conditions needed for common types of astronomical observation.

Observing Conditions

The following tables count the occurrence of the combinations of forecast and darkness conditions needed for different observations. Conditions are rated by by what percentage of the hours the observation would likely be attempted are usable.
Observation TypeMinimum conditions for hour to be usableOut of hours
Clear of CloudsTransparencySeeingSky Brightness
Planetary:50%(no limit)Average(no limit)Nighttime Hours
Deep Sky:70%Average(no limit)5.9Nighttime Hours
CCD Imaging:70%Below AveragePoor(no limit)Nighttime Hours

Percentages are of nighttime hours per month, or per year, when a particular observing conditions was met. Deep Sky percentages never exceed 50% because the moon is up half the time. Deep sky percentages are much lower for charts at high latitudes because of fewer dark hours in the summer.

Overall

PlanetaryData
Pts
Deep Sky
Max 60%
Data
Pts
Both Planetary and Deep Sky
Max 60%
Data
Pts
Either Planetary or Deep SkyData
Pts
CCD ImagingData
Pts
Night
58%
14531
23%
45501
19%
14487
63%
14487
30%
27215

By Month

MonthDays of MonthPlanetaryData
Pts
Deep Sky
Max 60%
Data
Pts
Both Planetary and Deep Sky
Max 60%
Data
Pts
Either Planetary or Deep SkyData
Pts
CCD ImagingData
Pts
January1st to 15thNight
41%
720
26%
2148
13%
716
52%
716
30%
1303
January16th to endNight
37%
768
26%
2304
15%
768
46%
768
26%
1473
February1st to 15thNight
40%
704
27%
2112
13%
701
50%
701
31%
1288
February16th to endNight
35%
631
23%
1893
12%
631
43%
631
27%
1216
March1st to 15thNight
42%
654
23%
2094
14%
654
50%
654
24%
1329
March16th to endNight
52%
576
25%
2019
20%
576
60%
576
31%
1108
April1st to 15thNight
50%
539
25%
1797
20%
539
59%
539
29%
1047
April16th to endNight
56%
525
27%
1750
24%
525
65%
525
37%
926
May1st to 15thNight
64%
494
22%
1649
22%
494
68%
494
30%
953
May16th to endNight
72%
514
20%
1696
21%
513
75%
513
33%
949
June1st to 15thNight
80%
495
14%
1485
16%
495
80%
495
34%
896
June16th to endNight
79%
495
15%
1455
16%
495
79%
495
31%
915
July1st to 15thNight
82%
465
14%
1428
16%
465
82%
465
30%
888
July16th to endNight
77%
522
9%
1632
12%
489
77%
489
24%
1053
August1st to 15thNight
85%
494
13%
1638
17%
491
85%
491
32%
964
August16th to endNight
75%
525
14%
1750
16%
525
75%
525
25%
1120
September1st to 15thNight
70%
495
21%
1650
23%
495
71%
495
24%
1049
September16th to endNight
73%
643
27%
1801
23%
643
74%
643
35%
1099
October1st to 15thNight
72%
660
33%
1874
27%
660
75%
660
48%
983
October16th to endNight
60%
704
35%
2112
29%
704
66%
704
42%
1122
November1st to 15thNight
60%
700
33%
2140
28%
700
66%
700
37%
1196
November16th to endNight
52%
720
31%
2340
25%
720
61%
720
35%
1284
December1st to 15thNight
45%
720
24%
2340
19%
720
52%
720
26%
1431
December16th to endNight
37%
768
20%
2394
14%
768
44%
768
21%
1623

Individual Forecasts

The length of each colored bar in the "occurrence of each Forecast" column is proportional to the number of times the chart forecast that color. The percentages are of the total number of hours per month, or per year, with a particular forecast. The colors as the same as those used in clear sky charts.

Note: Transparency probabilities are only counted for those hours that have 30% or less cloud cover. Seeing probabilities are only counted for those hours that have 80% or less cloud cover. If that's too tricky, try Observing Conditions instead.

Overall

Occurrence of each ForecastData
Points
Cloud CoverDay
11%5%25%5%35%5%6%8%38%
46090
Night
10%42442445%8%47%
45716
TransparencyDay
39%8%11%17%16%6%
45808
Night
33%7%13%19%17%8%
45503
SeeingDay
12%314%23%28%17%
4590
Night
12%418%30%26%8%
14533

By Month

Percentage Cloud Cover SE (2006-)
Color Meanings:
Overcast 90% covered 80% covered 70% covered 60% covered 50% covered 40% covered 30% covered 20% covered 10% covered Clear
MonthDays in MonthOccurrence of each ForecastData
Points
January1st to 15thDay
15%425%5%245%5%6%43%
1790
16th to endDay
20%42432333445%
1920
February1st to 15thDay
13%5%24422347%47%
1750
16th to endDay
16%5%35%433447%41%
1580
March1st to 15thDay
17%6%25%424445%42%
1875
16th to endDay
12%5%25%425%45%8%43%
2202
April1st to 15thDay
13%5%34435%6%6%8%39%
2151
16th to endDay
11%5%25%435%46%8%41%
2098
May1st to 15thDay
12%5%25%5%35%6%6%8%38%
1971
16th to endDay
10%435%6%36%6%5%9%38%
2060
June1st to 15thDay
7%5%26%7%5%8%7%8%11%29%
2145
16th to endDay
5%436%9%48%7%9%11%28%
2163
July1st to 15thDay
9%6%47%8%6%8%7%7%9%24%
2104
16th to endDay
8%6%47%8%5%8%8%9%11%20%
2108
August1st to 15thDay
8%7%26%8%48%8%8%12%25%
1980
16th to endDay
11%6%36%8%49%8%6%9%25%
2100
September1st to 15thDay
12%6%35%7%47%6%7%9%30%
1980
16th to endDay
9%426%6%36%5%6%8%39%
1817
October1st to 15thDay
6%4143345%47%55%
1753
16th to endDay
8%213433447%55%
1760
November1st to 15thDay
9%5%24223347%54%
1716
16th to endDay
9%413314345%56%
1620
December1st to 15thDay
14%7%34423446%43%
1620
16th to endDay
20%7%35%5%345%46%34%
1827
January1st to 15thNight
14%5%24423446%47%
2148
16th to endNight
20%5%2332443446%
2304
February1st to 15thNight
13%5%2432245%6%48%
2103
16th to endNight
18%6%25%223346%44%
1893
March1st to 15thNight
15%5%15%4345%47%42%
2094
16th to endNight
12%42322335%6%53%
2019
April1st to 15thNight
11%5%3442435%7%48%
1797
16th to endNight
8%31332345%9%52%
1750
May1st to 15thNight
8%414425%5%6%9%47%
1649
16th to endNight
43244345%6%11%49%
1695
June1st to 15thNight
43135%37%5%8%13%43%
1485
16th to endNight
5%3235%46%5%7%10%44%
1455
July1st to 15thNight
3434435%6%8%13%42%
1521
16th to endNight
5%325%6%36%6%9%14%34%
1752
August1st to 15thNight
3213426%7%9%14%42%
1650
16th to endNight
7%325%5%35%6%7%13%37%
1750
September1st to 15thNight
8%325%5%35%6%6%10%40%
1650
16th to endNight
6%6%245%245%5%8%48%
1801
October1st to 15thNight
4412313347%62%
1874
16th to endNight
10%323312345%60%
2112
November1st to 15thNight
9%41342335%6%55%
2140
16th to endNight
9%31333344456%
2340
December1st to 15thNight
13%5%25%424347%45%
2340
16th to endNight
20%6%35%423447%37%
2394

Transparency (when cloud cover <= 30%)
Color Meanings:
Too cloudy to forecast Poor Below Average Average Above average Transparent
MonthDays in MonthOccurrence of each ForecastData
Points
January1st to 15thDay
40%5%7%15%21%10%
1791
16th to endDay
42%45%16%20%9%
1920
February1st to 15thDay
36%5%9%16%22%10%
1752
16th to endDay
42%47%17%20%8%
1580
March1st to 15thDay
42%47%20%18%6%
1875
16th to endDay
38%5%9%19%21%6%
2204
April1st to 15thDay
37%8%9%18%17%7%
2151
16th to endDay
36%7%10%23%17%4
2098
May1st to 15thDay
39%8%11%22%12%6%
1971
16th to endDay
37%8%12%22%17%1
2064
June1st to 15thDay
41%11%15%20%9%1
2145
16th to endDay
43%10%17%18%9%
2163
July1st to 15thDay
47%13%17%16%4
1968
16th to endDay
47%14%20%14%2
1965
August1st to 15thDay
45%13%19%16%5%
1968
16th to endDay
48%14%15%12%6%2
2100
September1st to 15thDay
43%12%15%15%10%2
1980
16th to endDay
37%8%13%16%17%7%
1817
October1st to 15thDay
26%6%8%18%23%16%
1753
16th to endDay
27%46%14%28%18%
1760
November1st to 15thDay
29%47%17%30%9%
1716
16th to endDay
28%46%18%26%15%
1620
December1st to 15thDay
39%5%8%20%18%6%
1620
16th to endDay
49%6%6%16%16%4
1827
January1st to 15thNight
36%49%15%23%11%
2148
16th to endNight
42%35%14%23%10%
2304
February1st to 15thNight
36%47%18%21%12%
2112
16th to endNight
41%46%15%19%12%
1893
March1st to 15thNight
40%6%7%15%22%6%
2094
16th to endNight
31%412%19%23%7%
2019
April1st to 15thNight
34%5%10%22%16%10%
1797
16th to endNight
27%5%12%25%20%8%
1750
May1st to 15thNight
31%8%13%24%17%4
1650
16th to endNight
28%8%16%27%17%2
1697
June1st to 15thNight
28%10%22%27%10%
1485
16th to endNight
31%11%23%21%10%
1455
July1st to 15thNight
29%13%29%21%5%
1428
16th to endNight
33%14%28%20%1
1632
August1st to 15thNight
24%15%31%21%6%
1638
16th to endNight
35%12%26%15%6%3
1750
September1st to 15thNight
36%10%18%16%12%4
1650
16th to endNight
31%8%16%18%17%7%
1801
October1st to 15thNight
21%5%11%20%22%18%
1874
16th to endNight
26%36%15%26%21%
2112
November1st to 15thNight
30%37%17%28%12%
2140
16th to endNight
29%5%5%18%22%19%
2340
December1st to 15thNight
38%5%9%20%19%6%
2340
16th to endNight
47%5%6%18%15%6%
2394

Seeing (when cloud cover <= 80%)
Color Meanings:
Too cloudy to forecast Bad 1/5 Poor 2/5 Average 3/5 Good 4/5 Excellent 5/5
MonthDays in MonthOccurrence of each ForecastData
Points
January1st to 15thDay
18%5%38%22%14%
90
16th to endDay
23%18%40%14%2
96
February1st to 15thDay
14%13%31%32%7%1
90
16th to endDay
13%11%40%25%8%
81
March1st to 15thDay
23%7%42%24%2
90
16th to endDay
14%9%22%31%20%
188
April1st to 15thDay
16%8%26%26%19%2
270
16th to endDay
13%5%20%30%26%4
250
May1st to 15thDay
15%321%29%25%4
228
16th to endDay
11%18%26%31%20%
267
June1st to 15thDay
11%7%21%29%28%
255
16th to endDay
7%324%38%26%
368
July1st to 15thDay
8%15%20%35%28%
362
16th to endDay
9%111%33%42%
270
August1st to 15thDay
9%1310%35%39%
253
16th to endDay
8%2416%35%34%
268
September1st to 15thDay
14%15%18%35%25%
255
16th to endDay
13%425%40%15%
254
October1st to 15thDay
315%31%36%13%
193
16th to endDay
14%314%38%20%8%
96
November1st to 15thDay
26%120%31%16%4
90
16th to endDay
7%11%35%25%15%4
90
December1st to 15thDay
17%8%37%23%10%2
90
16th to endDay
34%7%21%22%11%2
96
January1st to 15thNight
17%6%30%36%9%
720
16th to endNight
22%8%27%32%8%
768
February1st to 15thNight
16%7%33%31%10%
704
16th to endNight
20%7%32%33%5%
631
March1st to 15thNight
17%8%27%35%11%
654
16th to endNight
13%6%22%36%20%
576
April1st to 15thNight
14%425%34%19%1
539
16th to endNight
11%223%37%22%2
525
May1st to 15thNight
9%115%43%26%2
495
16th to endNight
5%11%31%42%8%
515
June1st to 15thNight
6%426%50%12%
495
16th to endNight
41418%46%24%
495
July1st to 15thNight
5%212%52%26%
465
16th to endNight
4214%45%31%
522
August1st to 15thNight
3210%47%35%
494
16th to endNight
9%213%46%27%
525
September1st to 15thNight
10%1314%47%22%
495
16th to endNight
11%5%30%44%6%
643
October1st to 15thNight
5%115%36%35%6%
660
16th to endNight
12%418%32%26%5%
704
November1st to 15thNight
10%419%38%22%5%
700
16th to endNight
10%6%25%37%17%1
720
December1st to 15thNight
14%7%27%33%15%
720
16th to endNight
22%8%26%30%11%
768
Page generated at 2017-04-26 16:21:48. Version ac04

Copyright 2017 A. Danko


Omega Centauri Observatory Clear Sky Chart | Charts Home